Reverse-running pump

ABSTRACT

The invention relates to the machine building industry and can be used for reverse-running pulsation-free high-pressure pumps. The aim of the invention is to improve the operating characteristics of pumps of a similar variety (and the manufacturability thereof). The inventive pump comprises a rotor with orifices and at least two displacers arranged therein, a working chamber, a barrier separating the increasing area from the decreasing area. The working chamber is formed by surfaces of an annular groove embodied in the end of the rotor in such a way that the inner surfaces thereof confine the working chamber in a radial direction and slide into contact with the barrier&#39;s surfaces. The orifices of the rotor containing the displacers are oriented in an axial direction and open out onto the annular groove in such a way that the continuations thereof form pockets on the inner surfaces of the groove, thereby confining the working area in the radial direction.

[0001] This invention relates to mechanical engineering and may be usedin high-pressure reversible pulseless pumps capable of operating both asmotor and pump (hereafter referred to as pump). Gaseous and liquidworking fluids are applicable.

[0002] The well-known high-pressure pulseless pump (RU 2123602)comprises housing with inlet and outlet ports, the rotor being mountedin the housing. Channels are provided in the rotor, wherein the slidevalves are situated, which reciprocate along the rotor in an axialdirection. Further, the general term displacer will be used instead ofthe slide valve. The pump comprises a mechanism being a plurality ofmembers installed inside the housing, which sets an axial mutualposition of the displacers in the channels of the rotor, a workingchamber, a partition, which separates suction and injection spaces, thuspreventing backstreaming of the working fluid between them. Thepartition is a special case of one of the insulating members, whichinsulating members imply any of the pump elements that prevent fluidleaking out of the pump cavities.

[0003] In this particular embodiment of the pump, from one side theworking chamber is restricted along the axis of rotation of the rotor bythe surface of one of the rotor's ends, which is in a sliding contactwith the partition and which is hereafter referred to as the first endof the rotor, and from the other side, by a regulating member which is,in fact, an axially movable insulating member. In the radial directionthe working chamber is restricted by the shaft surfaces and the innersurface of a hollow cylinder, which is mounted inside the housing and isnot able to rotate with the rotor. The pump also comprises meansconnecting cavities at both sides behind the longitudinally oppositeends of the displacers.

[0004] In this particular embodiment of the pump, the means areimplemented as a supporting and distributing member, which is mountedinside the housing and whose surface is in a sliding contact with thesecond end of the rotor. Furthermore, two disconnected cavities areprovided in the said end of the supporting and distributing member, towhich the channels in the rotor accommodating the displacers open. Oneof the cavities is connected by a channel with the inlet port, andanother one—with the outlet port. The cavities are located so that oneof the them is opposite the suction space and communicates via a channelwith the inlet port; another one is opposite the injection space and isconnected by a channel with the outlet port. Thus the cavities at bothsides behind the longitudinally opposite ends of the displacers areconnected, and thereby the displacer is balanced against the hydraulicforces of the working fluid, and the effect of the displacer volume onthe stability of the flow and the capacity of the pump is avoided. Onemore widely known practical embodiment of said means may be animplementation of channels in each of the displacers so that thechannels connect the cavities at both sides behind the longitudinallyopposite ends of the displacers.

[0005] As the closest prior-art a high-pressure reversible pulselesspump (RU 2115807) was chosen, which, as in the above example, compriseshousing with inlet and outlet ports, the rotor being mounted in thehousing. The channels are provided in the rotor, accommodating thedisplacers, which are capable of reciprocating along the rotor's axis ofrotation (longitudinally). The pump comprises a mechanism installedinside the housing, which sets a relative axial position of thedisplacers in the channels inside the rotor, a working chamber, apartition, which separates suction and injection spaces, thus preventingbackstreaming of the working fluid between them. The partition is, inessence, a particular case of one of the insulating members, whichmembers imply and will imply hereafter any of the pump members thatprevents working fluid leaking out of the pump cavities. In thisparticular embodiment of the pump, from one side the working chamber isrestricted in the axial direction by the end face of the rotor, which isin a sliding contact with the partition and is called here the first endof the rotor, and from the other side, by the inner surfaces of thehousing facing this end of the rotor. In the radial direction, theworking chamber is restricted by the surfaces of the shaft and innersurface of the housing. The pump also comprises means connecting thecavities at both sides behind the longitudinally opposite ends of thedisplacers. In this particular embodiment of the pump, the above meansare implemented as the supporting and distributing member mounted insidethe housing, whose end is in a sliding contact with the second end ofthe rotor. Furthermore, two disconnected cavities are provided in thesaid end of the supporting and distributing member, to which thechannels in the rotor accommodating the displacers open. One of thecavities is connected by a channel with the inlet port, and anotherone—with the outlet port. They are located so that one of the cavitiesis opposite the suction space and communicates via a channel with theinlet port, and another one is opposite the injection area and isconnected by a channel with the outlet port. Thus, the cavities at bothsides behind the longitudinally opposite ends of the displacer areconnected, and thereby the displacer is balanced against the hydraulicforces of the working fluid and the effect of the displacer volume onthe stability of the flow and the capacity of the pump is ruled out. Onemore widely known practical embodiment of aforesaid means may be theimplementation of channels in each of the displacers so that thechannels connect the cavities at both sides behind the longitudinallyopposite ends of the displacers.

[0006] It is an object of the invention to improve the operatingparameters of such pumps and simplify the manufacturability.

[0007] These problems have been solved by a design of the pump, whichcomprises housing with inlet and outlet ports, a rotor with channels,wherein at least two displacers movable along the rotor axis of rotation(longitudinally), a working chamber, a partition, separating suction andinjection spaces, insulating members, a member setting relative axialposition of the displacers, and a mechanism connecting the cavities atboth sides behind the longitudinally opposite ends of the displacers.According to the invention, the working chamber is formed by thesurfaces of an annular slot, which is made in the end of the rotor sothat its inner surfaces restrict the working chamber in the radialdirection and are in a sliding contact with the surfaces of thepartition. Furthermore, the displacers are located in the channelsprovided in the rotor. The channels are oriented longitudinally andextend in an axial direction, opening to the annular slot so that theprolongations of the said channels form recesses in the inner surfacesof the annular slot, which restricts the working chamber in the radialdirection (i.e., normal to the axis of rotation of the rotor).

[0008] The abovementioned features included into the design of the pumpprovide technical results, which improve the operating parameters of thepumps of this type due to the damping effect, which appears when thedisplacers approach the insulating member that restricts the workingchamber in axial direction. The damping effect prevents destruction andreduces wear of both the insulating member and the displacers being incontact with each other which enables the rotating speed of the pump tobe increased.

[0009] Furthermore, the vibrations of the displacers caused by thehydraulic forces of the fluid in the working chamber are reduced; thenoise generated by the displacers is also reduced and it becomespossible to reduce the consumption of materials, making the displacersless elastic and having lower bending strength for the same workingpressure. One more useful result is the reduction of internal fluidbackstreaming in the working chamber and the improvement of theconditions for the formation of the oil-film wedge between the surfacesof the partition and the annular slot.

[0010] Moreover, due to the radial restriction of the working chamber bythe surfaces of the annular slot, provided in the end of the rotor, therotor is relieved from the radial forces of the working fluid (unlikethat in other types of pumps, e.g. vane pumps, in which thedouble-acting pump operation has to be used to this effect).Consequently, radial vibrations of the rotor and the noise arisingthereby, as well as the fluid friction on the walls restricting theworking chamber in the radial direction, are reduced.

[0011] All the aforementioned features implemented in the pump's designresult in an increase of the efficiency and the service life of thepump, making it possible to use self-tightening end seals and tosimplify manufacturing technology with specified tolerances and sizes.This also leads to essential enhancement of the resistance to hydraulichammer and abrupt pressure jumps.

[0012] In common with the other types of pumps, this pump may have amulti-chamber design with several working cycles of the displacers perone rotor revolution and also may have a number of annular slots on bothsides of the rotor ends accomodating the working chambers which mayproperly communicate with each other according to the pump operatingconditions.

[0013] The entity of the invention is apparently described by theaccompanying drawings in the following figures:

[0014]FIG. 1 depicts a longitudinal sectional view of the pump

[0015]FIG. 2 depicts a cutaway perspective view of the rotor showing adisplacer and a push rod.

[0016] The pump (FIG. 1) comprises housing 1 with end plates 2 and 3.Rotor 5 is mounted inside housing 1 on shaft 4. Channels 6 are providedin the rotor 5, wherein the axially movable displacers 7 are located.The pump may comprise at least two and more displacers 7. Annularcylindrical slot (18 in FIG. 2) is provided in the end of rotor 5, whichis located opposite the end plate 2. Channels 6 accommodating displacers7 are made in rotor 5 so that they open to annular cylindrical slot 18and form recesses 8 in its inner cylindrical surfaces. In other words,annular slot 18 is provided in the end of rotor 5 so that it passesthrough channels 6 in rotor 5, wherein displacers 7 are located, theradial width of annular cylindrical slot 18 being less than that ofdisplacers 7. In the drawings of the present embodiment of the pump,channels 6 reach the end of rotor 5 and form recesses 8 in the innercylindrical surfaces of annular slot 18 throughout its depth. However,in other embodiments of the pump, channels 6 may not reach the end ofrotor 5 at some distance.

[0017] The pump comprises partition 9, which separates the injection andsuction spaces. (The suction space is connected with the inlet port andthe injection space is connected with the port; these are not shown forthe simplicity's sake). The surfaces of partition 9 are in a slidingcontact with the inner surfaces of annular cylindrical slot 18.Partition 9 is mounted on end plate 2 and may form a whole with the endplate. (In some embodiments of the pump, partition 9 may be fixed, beingaxially movable, and may interact with the means which clamp thepartition to rotor 5). Therefore, the working chamber is restricted bythe inner surfaces of annular slot 18 and the inner surface of end plate2.

[0018] The pump comprises a mechanism setting displacers 7 in relativeaxial position in channels 6 of rotor 5. In this embodiment of the pump,the mechanism is made as a closed cam slot 10 in the inner cylindricalsurface of housing 1. Furthermore, each displacer 7 is equipped withpush rod 11, which enters in a sliding contact with cam slot 10Cam slot10 is made so that displacers 7 located opposite the end of partition 9,are moved into rotor 5 at an equal distance, and a part of displacers 7at a distance from partition 9 is pulled out of rotor 5 and is in asliding contact with the inner surface of end plate 2.

[0019] The pump also comprises means connecting the cavities at bothsides behind the longitudinally opposite ends of displacers 7. In thisparticular embodiment of the pump, the means are implemented as a set ofchannels provided in each displacer 7 in such a way that said channelsconnect the cavities at both sides behind the longitudinally oppositeends of the displacers 7. The above-mentioned channels are not shown onthe drawing for simplicity. However, in general, the means connectingthe cavities at both sides behind the longitudinally opposite ends ofdisplacers 7, may be implemented in a variety of ways as well, forexample, using a supporting and distributing disk, which is described inthe closest prior-art of the invention (or using a plurality of saidmeans). This supporting and distributing disk may be installed to bemovable along the longitudinal direction of rotor 5.

[0020] Furthermore, the pump is designed so that the surfaces of the endof rotor 5, wherein annular cylindrical slot 18 is provided, which arelocated at different sides of annular cylindrical slot 18, are in asliding contact with the opposite end faces of seals 12, which arelocated on the inner surface of end plate 2 and may be integral with it.This makes it possible to reduce fluid leaking out of the workingchamber, because the working chamber becomes sealed over the end faces,and to reduce wear of the partition end face, which is in a slidingcontact with the rotor, due to an enlargement of the contact areabetween the rotor and insulating members of the pump.

[0021] In this embodiment of the pump, seals 12 are implemented as twohollow cylinders, mounted in annular slots 13, which are made concentricin the inner wall of end plate 2. These hollow cylinders are mounted sothat their cylindrical surfaces facing each other are in a contact withthe surfaces of partition 9, which are located outside of annularcylindrical slot (18 in FIG. 2) made in the end face of rotor 5.

[0022] This substantially simplifies the manufacturability of partition9 and its mounting guides (especially, in the embodiment with an axiallymovable partition and with a variable displacement).

[0023] The hollow cylinders are mounted in annular slots 13 and aremovable along the axial direction of rotor 5. This enables the hollowcylinders to follow the axial movement of rotor 5 (if the pump isequipped with proper means for the axial movement of the cylinders),being permanently in contact with it. This consequently enables stablesealing of the working chamber to be obtained during vibrations and theaxial shifts of the rotor, and the thermal expansion and wear caused byfriction of the pump components to be compensated. The means of theaxial cylinder movement are implemented as follows: at least onepass-through channel 14 is made in these hollow cylinders, which extendsfrom the cylinder end facing the rotor up to annular slot 13, whereinthe cylinder is mounted. By varying the cross-sectional area and theposition of channels 14 at the cylinder ends, the optimal force clampingsaid cylinders to rotor 5 can be chosen, thus optimizing the backlashand leaking, thereby reducing the friction wear of the contactingsurfaces.

[0024] The second end of rotor 5 is in contact with end plate 3. Slot 15is made in the inner surface of end plate 3, wherein at least one seal16 movable along the axis of rotor 5 is mounted. In this particularembodiment of the pump, two seals 16 are mounted in end plate 3, bothhaving pass-through channel 17, which extends from the end of the seal16 facing the end of rotor 5 up to annular slot 15, wherein seals 16 arelocated.

[0025]FIG. 2 depicts a cutaway perspective view of rotor 5 with onedisplacer 7 and push rod 1 I to demonstrate annular slot 18 and recesses8 on the inner surface of the rotor.

[0026] The pump operates as follows.

[0027] After starting the pump, while rotor 5 is rotating, push rods 11start to slide within closed cam slot 10 and to reciprocate along theaxis of rotation of rotor 5, thereby moving displacers 7. Cam slot 10 ismade so that the movement of displacers 7 per one revolution of rotor 5is characterized by the following cycle: displacer 7, which is oppositethe end of partition 9, is pulled into rotor 5 and does not move alongits axis of rotation. As displacer 7 moves away from partition 9, itstarts being drawn out of channel 6 in rotor 5 to the cylindricalannular slot's cavity 18, and then sliding along the surfaces ofrecesses 8 (which are the additional guides for the displacer), andthen, at some instant displacer 7 touches the inner surface of end plate2. After that, displacer 7 slides with its end along the inner surfaceof end plate 2 without axial movement relative to rotor 5. As displacer7 approaches partition 9, it starts being gradually pushed into rotor 5,until it passes partition 9 being pushed into rotor 5 up to the end.While sliding on the inner surface of end plate 2, displacer 7 separatesthe injection and suction spaces in the cylindrical annular slot 18.

[0028] In a general embodiment of the pump, a segment of end plate 2over which displacers 7 slide may be implemented as an axially movableinsulating member (variable displacement pump embodiment).

[0029] The working fluid, confined between two neighboring displacers7and also found in channels 6, wherein the displacers 7 are located,starts to be transported from the suction to the injection space,wherein the low and high working pressure areas are produced, which arerespectively connected with the inlet and outlet ports (the process isdescribed in more detail the prior art patent).

[0030] The working fluid tends to stream through the backlashes betweenthe insulating members from the injection to the suction space. Incylindrical annular slot 18the injection space is separated from thesuction space by partition 9 and displacer 7 whose end is in a slidingcontact with the inner surface of end plate 2.

[0031] The pressure of the working fluid, which is in the injectionspace, tends to move a part of displacer 7 pulled into cylindricalannular slot 18 towards the suction space, thus tending to bend anddeform said displacer 7. However, recesses 8 accomodating the part ofdisplacer 7 pulled into cylindrical annular slot 18 prevent thedeformation and bending of displacer 7.

[0032] Recesses 8 act as additional guides for displacers 7, preventingbending and vibration of displacers 7 by the fluid pressure in theworking chamber (with especial strength the effect is exhibited in theembodiment with cylindrical displacers 7). Accordingly, aforementionedeffect reduces the noise generated by displacers 7 and enables themanufacture of displacers 7with lower material consumption, shorter inlength, less elastic and stiff, for the same working pressure.Furthermore, it allows reducing the dimensions and the weight of thepump in comparison with the prior-art.

[0033] On more useful result of the presence of recesses 8 in the innersurfaces of cylindrical annular slot 18 is the reduction of thebackstreaming and the relaxed requirements for the tolerance ofdisplacers 7 for fitting the shape of channels 6; displacers 7 areclamped to the surfaces of recesses 8 by the fluid pressure, therebyproviding better sealing between the surfaces of displacers 7 andrecesses 8. Furthermore, since the fluid passes through the segmentswith different cross-sectional areas, the sealing produced by partition9 between the suction and injection spaces is improved as well as forthe oil-film wedge formation between surfaces of partition 9 and annularslot 18 accommodating partition 9.

[0034] Besides, due to the radial restriction of the working chamber bythe surfaces of annular slot 18, provided in the end face of rotor 5,rotor 5 is relieved from the radial forces of the working fluid (incontrast to many other kinds of pumps, e.g. vane pumps, in which thedouble-acting pump operation is used to this effect). Consequently,radial vibrations of the rotor, and the noise and instability of therotation of rotor 5 arising thereby, as well as the fluid friction onthe walls restricting the working chamber in the radial direction andlosses due to the friction of displacers 7 on these walls, are reduced.

[0035] Recesses 8 on the surfaces of cylindrical annular slot 18 producethe damping effect and allow it to be controlled (which is adjusted byselecting appropriate dimensions and a depth of recesses 8). The dampingeffect is observed while displacers 7 approach the inner surface of endplate 2restricting the working chamber in the axial direction. Thedamping effect arises due to prevailing backstreaming of the workingfluid along recesses 8 (while they are connected with the low-pressureareas in the pumping chamber) from the high-pressure areas in thepumping chamber, while the displacer approaches the inner surface of endplate 2 and shuts aforementioned recesses 8. At that moment, the workingfluid is compressed and tends to move displacer 7 away, therebypreventing its end from an abrupt impact on the inner surface of endplate 2. (This effect is exhibited especially strongly in the embodimentof the pump, in which displacers 7 are provided with the protrusions attheir ends (not shown for the simplicity's sake), facing end plate 2 andlocated in the recesses. In this case, the protrusions primarily shutrecess 8, producing a closed space inside it; hence the damping effectdepends on the dimensions and shape of the protrusions).

[0036] The damping effect prevents destruction and reduces wear of boththe inner surface of end plate 2 and displacers 7 which are in a contactwith the end plate; this allows the rotating speed of the pump rotor 5to be increased.

[0037] Seals 12 are implemented as two hollow cylinders, mounted inannular slots 13 and axially movable along the axis of rotor 5,following possible axial shifts of rotor 5, being permanently clamped tothe rotor. The clamping is due to the fact that the working fluid,flowing from the injection space of the pump into the backlash under theend faces of seals 12 clamped to rotor 5, tends to force out seals 12from the rotor. In this case, the working fluid flows under pressurefrom the backlash, through channels 14, into annular slots 13, thusbalancing the fluid pressure in channel 14 and annular slot 13. Sincethe whole area of seal 12 is under the working fluid pressure fromannular slot 13, whereas from the rotor side the pressure acts near theinjection space of the pump only, the optimal force, clamping the rotor5 to seals 12 implemented as cylinders, is obtained by a properselection of the cross-sectional area and the location of channels 14 atthe ends of seals 12. Furthermore, by connecting annular slots 13 with athrottle (not shown on the drawings for the simplicity's sake) and byadjusting the working fluid flow through the throttle, it is possible tooptimize the backlash between seals 12 and end faces of rotor 5contacting with them.

[0038] The operation of seals 16 is similar to that of seals 12.

[0039] It should be noted, that the pump is generally manufactured sothat all the members, contacting with end faces of rotor 5 (as well aspartition 9) may be designed axially movable and comprising means ofself-tightening to the end faces of rotor 5, similar to the means of theaxial movement of seals 12.

[0040] It should be also clarified that the rotation of the rotor isalways referenced relative to the housing of the pump, no matter onwhich device the housing may be mounted to provide rotation of the rotorrelative to the housing. In many practical cases of the pump usage, thepump's member referred to as housing may be mounted on the rotatingshaft of the given device, whereas the pump's member called the rotormay be mounted on a frame or other rotating shaft of the same device.

We claim:
 1. A reversible pump, which comprises a housing with inlet andoutlet ports, a rotor provided with channels, wherein at least twoaxially movable displacers are located, a working chamber, a partition,separating suction and injection spaces, insulating members, a pluralityof members setting mutual axial positions of said displacers, meansconnecting cavities at both sides behind the longitudinally oppositeends of the displacers, said working chamber restricted in radialdirection by the surfaces of an annular slot, provided in the end ofsaid rotor and extending through said channels in the rotor, whereinsaid displacers are located, and recesses in said annular slot surfacesformed by the intersection of said channels with said annular slot,wherein surfaces of said partition are in a sliding contact with saidsurfaces of an annular slot.
 2. The pump, according to claim 2, whereinsurfaces of the end of the rotor provided with the annular slot, opposedwith respect to said annular slot, are in a sliding contact with theends of seals, mounted opposite said surfaces of the rotor.
 3. The pump,according to claim 2, wherein seals are implemented as hollow cylinders,mounted in annular slots provided in the housing.
 4. The pump, accordingto claim 3, wherein the hollow cylinders are axially movable along anaxis of rotation of the rotor.
 5. The pump, according to claim 4,wherein the hollow cylinders are provided with at least one pass-throughchannel, extending from the end of the cylinder facing the rotor endtowards an annular slot, wherein said cylinder is mounted.
 6. The pump,according to claim 1, wherein at least one seal axially movable alongthe axis of rotation of the rotor is mounted opposite the second end ofthe rotor, wherein the seal is provided with at least one pass-throughchannel, extending from the end of the seal facing the rotor end towardsan annular slot, wherein said seal is mounted.